1. Field of the Invention
The present invention relates to a coordinate input device having a display unit superposed on a position detecting tablet and capable of displaying a position which is indicated by a magnetic body on the position detecting tablet.
2. Description of the Prior Art
Hitherto, a coordinate input apparatus having a tablet for inputting hand-written calligraphic characters and patterns and a display unit for displaying the result of such calligraphic specimen and patterns with the tablet and the display unit being constructed independently and disposed separately from each other, has been proposed. With this type of apparatus, however the user is obliged to watch both the tablet surface and the display surface alternately, in order to confirm that the hand-written characters and patterns scribed on the tablet have been correctly recognized and input. Consequently, the work of inputting a sentence by handwritting is impeded thereby reducing the efficiency of the work. In addition, editing operation such as correction and insertion of words and characters requires the moving of a cursor to the position where correction or insertion is to take place. This operation is quite troublesome because the user has to simultaneously move the cursor and confirm the present position of the cursor and the desired word or character in the document.
On the other hand, an input/output device having a tablet and a display unit integrated with each other has been proposed recently in, for example, Japanese Patent Laid-Open No. 144287/1983. In this apparatus, any desired position in a document on display can be indicated on the tablet directly by means of a stylus pen connected to a character recognition circuit, thus facilitating the editing and input/output operations. With this apparatus, therefore, the user can write a sentence simply by drafting the sentence in accordance with the input format observed on the tablet, with the same ease as that of laying out and scribing directly on output paper.
This input/output device, however, suffers from the following disadvantages. Namely, the writing operation for writing the characters and patterns in the writing section of the tablet is inconveniently hindered by the cord connecting the stylus pen to the character recognition circuit. In addition, the stylus pen has to be moved in contact with the tablet or in the close proximity of the tablet in order to attain a highly precise indication of the characters.